[SR-71]

Does anyone make or modify an EFI system like the ones FiTech makes as pictured to fit a 400-455 Pontiac engine?

[Tom Vaught]

I have seen a couple of modified intakes, done by Luhn Performance that used a Pontiac Dual Quad lower intake (with Injector Bosses added) and a LS upper and lower plenum attached to the Pontiac Intake.
I did one using a Nash/Warrior lower TR Intake and the parts in this post to make a EFI Intake.

You can trim and modify the intake length by cutting and tig welding but I would just buy the piece on the far right, drill some holes to mount your piece to the intake you want to run and then add the top piece (on the left) and a throttle body.

Tom V.

[AIR RAM]

Originally Posted by SR-71

Does anyone make or modify an EFI system like the ones FiTech makes as pictured to fit a 400-455 Pontiac engine?

Originally my goal was to run the Holley High Ram upper plenum top seen above in Tom V's pic and mount it to a BDS Blower intake with a 3-4" inner-cooler mounted below it. I felt that the inner-cooler would help organize the air and remove some turbulence before entering the low profile blower intake. I would still like to do this some day however I took an easier way out. One thing I did NOT like about the blower intake was that the runners are NOT separated (Non existent) and your runner lengths are literally the split in the head.... The intake has no runners. This is what turned me away.

I will be running a North Wind Intake set up for MPFI and top it off with a low profile throttle body elbow so I can mount a large bore LS throttle body. Holley makes a real low profile elbow that only adds approximately 3" of height to the top of the intake manifold. This should allow most single plane intakes to clear most hoods.

SPEED SAFE, NICK

[SR-71]

I would think that it would sell and offer a more modern look to add fuel injection to older engines. I wonder how they would flow and work with stock "good" heads.

[AIR RAM]

I mis spoke in my above post... its Edelbrock who makes the low profile throttle body elbow not Holley.

The beauty is that the set up with the NW intake and Elbow is literally begging to be blown!

SPEED SAFE, NICK

[AIR RAM]

Originally Posted by SR-71

I would think that it would sell and offer a more modern look to add fuel injection to older engines. I wonder how they would flow and work with stock "good" heads.

If it where carbureted I would think a single plane would be to dependent on the air flow through the carb and low end torque would suffer in favor of upper RPM power... however the same set up but Multi Port Fuel Injected would not rely on the air flow to pull metered fuel into the intake then into the runners... so at that point runner velocity would be your main concern.... the PCM would add the appropriate amount of fuel per the tune... I would put my money on a Fuel Injected Single Plane to offer great all round performance... But dont ask me... Ask Tom V.... he's most likely has first hand experience.

SPEED SAFE, NICK

[Tom Vaught]

You are correct about the air flow and carb signal from the engine events having an effect on the carb boosters and how well they operate under all conditions.

Dual carbs tend to allow a straighter shot at the boosters vs a single carb application.

With EFI, the air just gets into the plenum thru the throttle body.
The issue is where does the majority of the air go? Lousy goose neck adapters mean lousy fuel distribution.

If most of the air packs up in the back of the intake then the rear cylinder need more fuel to have a "Non-lean" air/fuel ratio.

If the air passing thru the intake blows by the front runners then less air there and the front cylinders need to have a leaner fuel calibration.

Modern EFI systems do a good job on this with individual injectors per runner systems and tuning capabilities..

The EFI/carb clones basically just help you not do jet changes. No real tuning per cylinder as most are batch fire on the injectors.

So just because you have a simple throttle body on the front of a goose-neck adapter going to the intake manifold does not mean even distribution of the air and same fuel requirement per cylinder. Some low profile goose-necks are really lousy air distribution parts.

Tom V.

[AIR RAM]

Originally Posted by Tom Vaught

You are correct about the air flow and carb signal from the engine events having an effect on the carb boosters and how well they operate under all conditions.

Dual carbs tend to allow a straighter shot at the boosters vs a single carb application.

With EFI, the air just gets into the plenum thru the throttle body.
The issue is where does the majority of the air go? Lousy goose neck adapters mean lousy fuel distribution.

If most of the air packs up in the back of the intake then the rear cylinder need more fuel to have a "Non-lean" air/fuel ratio.

If the air passing thru the intake blows by the front runners then less air there and the front cylinders need to have a leaner fuel calibration.

Modern EFI systems do a good job on this with individual injectors per runner systems and tuning capabilities..

The EFI/carb clones basically just help you not do jet changes. No real tuning per cylinder as most are batch fire on the injectors.

So just because you have a simple throttle body on the front of a goose-neck adapter going to the intake manifold does not mean even distribution of the air and same fuel requirement per cylinder. Some low profile goose-necks are really lousy air distribution parts.

Tom V.

Understood... I remember a while back reading a tread about different types of intakes and how they performed under boost, the main topic was about how the rear runners would run leaner than the front due to the incoming air charge.

I also completely get your point about this same phenomenon having a very probable obstacle with the intake/elbow set up I am planning on running.

The Edlebrock elbows I have been looking at may not be perfect however I think I can work with them... They do have a large divider cast into the center of them which I would think would help minimize the charge to the back half of the intake manifold. So there would be some amount of "redirection" forcing the air charge to the center of the manifold.

I was planning on making a thin plate with a "curtain" welded to the plate that literally just fit into the inner dimensions of the 8150 cut out that dropped down approximately an inch into the plenum. The idea was to extend the track of the elbow an inch into the manifold in an attempt to complete the "re-direct" and focus the air more naturally to the center of the intake rather than aft heavy... Im not sure if that makes any sense or not...

My concern is negatively effecting intake flow if the curtain idea extended to far into the manifold. However if I can hang that curtain just far enough to redirect the majority of rearward energy to aim to the intake floor I think it could end up with more control over the AFR between cylinders without removing volume or placing an obsticle directly in the air stream which would slow the air down... Not trying to do that.

A spacer may aid in adding volume to the total set up... if the hood allows it.

What are your thoughts...

SPEED SAFE, NICK

[SR-71]

I was interested in the low profile LS style intake as I pictured for a non turbocharged application. I do appreciate all the feedback as well.

[Harold Washington]

Larry Wenzler was developing a top like the Holley top for his intake.

[HWYSTR455]

I will be running the Edelbrock low profile elbow and an LS DBW TB on a Victor EFI intake. Before I went down this road I spoke to a number of people, due to concerns of air distribution. The Edelbrock guys I spoke to after numerous calls basically told me that it's not as much of a factor as some may believe, and they did some ridiculous hours of testing with the low elbow specifically. He commented that you want to use an open plenum intake, and the taller they are the better. The divider was placed and sized, to maximize the distribution. The amount of air flow discrepancies are so low it was not a great concern.

Yes, you can go custom, and have something made, but you all know what that means. $$$$$. And the gains will be arguable I bet.

I plan on monitoring EGTs and plug readings, as well as overall AFRs. But for anything other than an all-out strip car, I suspect it will be fine. Give me a few weeks and I will have actual data. But have seen several others who have used a similar setup and are satisfied.


.

[AIR RAM]

Originally Posted by HWYSTR455

I will be running the Edelbrock low profile elbow and an LS DBW TB on a Victor EFI intake. Before I went down this road I spoke to a number of people, due to concerns of air distribution. The Edelbrock guys I spoke to after numerous calls basically told me that it's not as much of a factor as some may believe, and they did some ridiculous hours of testing with the low elbow specifically. He commented that you want to use an open plenum intake, and the taller they are the better. The divider was placed and sized, to maximize the distribution. The amount of air flow discrepancies are so low it was not a great concern.

Yes, you can go custom, and have something made, but you all know what that means. $$$$$. And the gains will be arguable I bet.

I plan on monitoring EGTs and plug readings, as well as overall AFRs. But for anything other than an all-out strip car, I suspect it will be fine. Give me a few weeks and I will have actual data. But have seen several others who have used a similar setup and are satisfied.


.

Thanks for the pics... at least now I can see what my combo will look like. The only reason I did not go with the victor and went with the NW was because I was concerned with hood clearance... Are you able to get hood closed without contact with the way it is now?

Also, It appears that you are using an electronic throttle body... I was planning on sticking with the cable... however I am interested as to what PCM/ software you plan to control everything with.

Thanks for sharing!!!!

SPEED SAFE, NICK

[HWYSTR455]

Yes, drive by wire TB. It's a CTS-V one, with the solenoid off to the side for added clearance. I tried a couple vette ones and they didn't clear by about a 1/2". It's close. I have about an inch, maybe inch and a quarter clearance with the hood closed.

Hoods slope down towards the front, so it gets lower/tighter the further you go forward. But, you could go off to the side, or even the rear if you absolutely had to.

If you go to the side, and your intake is too low, or your rails are too high, the elbow won't clear the rails. But you could always use base spacers and creep up on it. I've seen a couple 2nd gen 'birds go to the side, no problem. (As long as you don't have short body bushings.).

If I would have not had enough room, I would have gone to a NW. But the 68-72 A-bodies have considerable room, and shouldn't be too difficult to work it out.

Using a Holley Dominator EFI ECU, Holley 48# injectors, and Edelbrock fuel rails. You can check out my build thread, but honestly, I've been bad about keeping up with it. I want to get the project done, almost there, and any spare time I have I am in the garage!


.

[AIR RAM]

Originally Posted by HWYSTR455

Yes, drive by wire TB. It's a CTS-V one, with the solenoid off to the side for added clearance. I tried a couple vette ones and they didn't clear by about a 1/2". It's close. I have about an inch, maybe inch and a quarter clearance with the hood closed.

Hoods slope down towards the front, so it gets lower/tighter the further you go forward. But, you could go off to the side, or even the rear if you absolutely had to.

If you go to the side, and your intake is too low, or your rails are too high, the elbow won't clear the rails. But you could always use base spacers and creep up on it. I've seen a couple 2nd gen 'birds go to the side, no problem. (As long as you don't have short body bushings.).

If I would have not had enough room, I would have gone to a NW. But the 68-72 A-bodies have considerable room, and shouldn't be too difficult to work it out.

Using a Holley Dominator EFI ECU, Holley 48# injectors, and Edelbrock fuel rails. You can check out my build thread, but honestly, I've been bad about keeping up with it. I want to get the project done, almost there, and any spare time I have I am in the garage!

.

Is there a reason you went with the electronic "Fly by wire" throttle body over cable? I would assume that the cable would be better for throttle response however now that I think about it, the FBW it would make adding a cruise control much easier... Its nice to know that the Deliminator EFI ECU can control that.... I may consider going FBW throttle body as well.

Make sure you take engine twisting into consideration under WOT load... If it twists enough it could end up kissing the underside of the hood. I plan to run front/mid plates on mine.

How much clearance do you have over your water neck? I was planning to run a cooling block there which adds like 2" of height...

Again, thanks for sharing your information!!!

SPEED SAFE, NICK

[HWYSTR455]

Sorry, just saw this, some reason didn't get notified back when.

I did DBW because I knew it would be lower than a cable one. The cable ones have a 'cam' for the cable, and it sticks up over the body.

I have about 3/4", and even when the engine torques, it doesn't contact. And throttle response is not an issue.

The water neck is close, about 1.5".

Sadly, you have to mock it all up and just see. I had to shuffle throttle bodies until I found the best one.

A Northwind would do it easily, but you would have to have injector bungs installed.

.

[JC455]

I’m currently working on a manifold like Tom V showed, but I also have this one.
It’s a copy of the PPR Tomahawk manifold. This one has PRO COMP on a runner, but I have another with no name on it. You can find them on eBay for under $150.
I chose this one for clearance under shaker scoop on a 2nd gen.

[JC455]

Also, Holley Terminator X Max has DBW and a tranny controller built into it, if you're wanting EFI and an OD auto trans (and DBW, or not)- it's a heck of a deal for what it is.

[AIR RAM]

I’m starting to get all my parts pieced together. This is what I’ll be using for my induction system. This gets me a super low profile, I will add as much spacer as I can fit under the hood to ease transition and add volume.

I’m not exactly sure what throttle body I will be running however it will be either a dual or mono blade throttle body. Undecided on size as well... but the good news is there are lots of options for this plenum.

SPEED SAFE, NICK

[Tom Vaught]

Originally Posted by AIR RAM

"I will add as much spacer as I can fit under the hood to ease transition and add volume." SPEED SAFE, NICK

I would suggest putting two play putty balls on the "elbow" (one at the T/B location, and one at the center of the intake plenum on the top of the elbow and close the hood a few times.

If you have a engine retention strap on the drivers side you should be able to figure out the spacer height fairly easily. Extra volume in that spacer height really helps with getting the air more evenly to the runners on a engine when you are NA or are off Boost..

Tom V.

[AIR RAM]

Originally Posted by Tom Vaught

I would suggest putting two play putty balls on the "elbow" (one at the T/B location, and one at the center of the intake plenum on the top of the elbow and close the hood a few times.

If you have a engine retention strap on the drivers side you should be able to figure out the spacer height fairly easily. Extra volume in that spacer height really helps with getting the air more evenly to the runners on a engine when you are NA or are off Boost..

Tom V.

Absolutely... great advice. I will definitely verify hood clearance and then add as much spacer as it will take.

I will also be running a mid and front plate so I may be able to drop the engine a hair as well. The plates will prevent any movement so I can really take advantage of the clearance. I plan to cross that bridge when I get their, really not sure how much I can safely drop the engine before the oil pan vs road start getting into the equation.

SPEED SAFE, NICK